Johnson et al. (2006) and Eizirik et al. (submitted) placed the Borneo Bay Cat (Catopuma badia) with the Asiatic Golden Cat (C. temminckii) and Marbled Cat (Pardofelis marmorata) in the genus Pardofelis, representing one of the earliest felid radiations (O'Brien and Johnson 2007). The Borneo Bay Cat is not a small island form of the Asiatic Golden Cat, as previously thought, having diverged from its extant relatives approximately four million years ago, well before the separation of Borneo from the mainland (Johnson et al. 1999, O'Brien and Johnson 2007).

An evaluation of skull morphology by Sicuro and Oliveira (2011) revealed that skull structure in Pardofelis is quite different from that in Catopuma. Moreover, Pardofelis has a flexible ankle joint and elongated tail, presumably adaptations to arboreality, which are lacking in Catopuma. Based on these morphological differences and the early split of the Asiatic Golden Cat and the Borneo Bay Cat from the Marbled Cat in the Late Miocene (5.86 Mya), the Cat Classification Task Force of the IUCN SSC Cat Specialist Group retains both the Borneo Bay Cat and Asiatic Golden Cat in Catopuma (CCTF in prep.)

Justification:
The Borneo Bay Cat, a Bornean endemic, remains one of the least known and infrequently recorded of the world’s wild cats, hindering efforts to assess its conservation needs and status. Historical records, incidental observations, and more recently, camera trap photographic captures and a niche modelling exercise (Hearn et al. submitted) indicate that this elusive felid appears restricted to natural and semi-natural forest cover but, within such habitat, exhibits some degree of habitat plasticity. Importantly, however, the extensive areas of swamp forest and oil palm plantations on Borneo do not appear to be used by this felid. A Maximum Entropy (MaxEnt) based habitat suitability analysis, using presence-only data coupled with expert opinion, estimated that the Bay Cat’s current area of occupancy (AOO) extends to approximately 221,000 km2 (Borneo Carnivore Symposium 2011, Hearn et al. submitted). Due to a lack of sufficient data, this analysis was unable to account for the potential impacts of differential hunting pressure on population density throughout this range. Hunting could plausibly be having a considerable impact on the species and our distribution estimate may, therefore, represent an optimistic estimation of the current AOO. A GIS exercise as part of the current assessment used the habitat suitability assessment alongside landcover data for Borneo for the years 2000 and 2010 (Miettinen et al. 2010) and showed that the estimated AOO decreased by 29.8% during this time period, primarily as a result of forest loss and conversion to oil palm. More recent satellite imagery shows that forest loss has continued to reduce the AOO in size (Gaveau et al. 2014), and it is likely that forest loss continues to this day, albeit at a reduced rate. In addition, some protected areas in Borneo are small, fragmented and isolated making them vulnerable to climate change and ineffective in conserving low-density species such as the bay cat (Scriven et al. 2015). Because the species spends time on the ground, Bay Cats are prone to untargeted snaring and there is increasing evidence for the capture and export of Bay Cats for the illegal pet market. We estimate that the cumulative reduction in the population size as a consequence of degradation, poaching amounts and forest conversion, to between 20-30% in the past 12 years (two Bay Cat generations, Pacifici et al. 2013).

No population density estimates exist for this felid. Nevertheless, the paucity of Bay Cat specimens collected during the nineteenth and twentieth centuries caused earlier authors to conclude that the species is naturally rare, a stance further bolstered by recent camera survey efforts. Indeed, photographic capture rates of the Bay Cat are substantially lower than that of the sympatric Sunda Clouded Leopard (Neofelis diardi), which is estimated to exist at low densities (1-4 individuals 100 km2: Brodie and Giordano 2012a, Wilting et al. 2012, Sollmann et al. 2014, Loken et al. unpublished data) leading some authors to hypothesize that the Bay Cat is found at even lower densities (Azlan and Sanderson 2007, Mohamed et al. 2009, Ross et al. 2010, but see Wearn et al. 2013). Acknowledging that our estimate of current AOO may be biased high as a result of unmeasured hunting pressure and a patchy distribution, we take a precautionary approach and estimate that the mean density of the Bay Cat across the AOO may be as low as one individual per 100 km2. Extrapolation of this estimate to the wider AOO suggests that the number of mature individuals could plausibly be fewer than 2,500 individuals indicating, in combination with the estimated past decline rate (>30% in the past 12 years), a categorization of Endangered under EN C1.

The Borneo Bay Cat is endemic to the island of Borneo, and until recently, its distribution was poorly understood. Although somewhat hindered by the low number of Bay Cat records, Meijaard (1997) collated historical records and contemporary observations of the Bay Cat and speculated that this felid was, and possibly still is, widely distributed on Borneo, a proposition later supported by Azlan and Sanderson (2007). Bolstered by the increasing number of Bay Cat records obtained from chance sightings (Bricknell 2003, Hearn 2003, Meijaard et al. 2005) and the increasing, but still relatively few camera trap records (Azlan et al. 2003, Yasuda 2007, Mohamed et al. 2009, Ross et al. 2010, Bernard et al. 2012, Brodie and Giordano 2012b, Wearn et al. 2013, Sastramidjaja et al. in press, Hearn et al. unpublished data), a MaxEnt habitat suitability modelling approach was developed during the Borneo Carnivore symposium in 2011 from presence-only and expert opinion data in combination with environmental and landuse covariates to make predictions regarding the current distribution of Bay Cats (Hearn et al. submitted). In support of Meijaard (1997), Hearn et al.’s (submitted) model predicted that an extensive, contiguous, forested area of interior Borneo, in addition to a number of more isolated forested fragments, amounting to approximately 221,000 km2, may be currently occupied by the Bay Cat. Due to a lack of data, the habitat suitability exercise was unable to account for the potential impact of differential hunting pressure throughout this range, which potentially could be having a considerable impact, and our estimate may therefore represent an overly optimistic estimation of the current area of occupancy (AOO). Recent records of the Bay Cat stem from the Malaysian states of Sabah (Kitchener et al. 2004, Mohamed et al. 2009, Ross et al. 2010, Bernard et al. 2012, Wearn et al. 2013, Hearn et al. unpublished data) and Sarawak (Dinets 2003, Azlan et al. 2003, Hon 2011, Brodie and Giordano 2012b, Mathai et al. 2014), the Indonesian provinces of East (Yasuda et al. 2007, Sastramidjaja et al. in press), West (Hearn 2003, Meijaard et al. 2005), and Central (Bricknell 2003) Kalimantan, and Brunei (J. Sanderson pers. comm.). No records of the Bay Cat have been made in South Kalimantan, yet it is unknown whether this represents a genuine absence or a lack of sufficient sampling effort.

The map presented as part of this assessment is largely based on this habitat suitability exercise, but small patches which were identified as non-habitat in the model output have been included here as habitat. In addition, the Tabin Wildlife Reserve, not included in the original model output, has been included here, based on recorded presence (Ross et al. 2010, Bernard et al. 2012, Gardner et al. 2014).

Most Bay Cat records are from below 800 m but Brodie and Giordano (2012b) describe two records from above 1,400 m in the Kelabit Highlands and Payne et al. (1985) mention an unconfirmed record from 1,800 m on Mt. Kinabalu.

There are no population density estimates for the Borneo Bay Cat in any part of its range, yet this elusive felid has long been considered uncommon. Noting the paucity of specimens collected during the nineteenth and twentieth centuries, earlier authors concluded that the species was naturally rare. Even now, the Bay Cat is known from only 12 specimens (Sunquist and Sunquist 2002, Kitchener et al. 2004), and incidental observations remain few and far between (Bricknell 2003, Hearn 2003, Meijaard et al. 2005). Since the advent of intensive camera trap surveys, however, many of them targeted at felids, there has been a slow but steady rise in the number of photographic captures of this felid (Azlan et al. 2003, Azlan and Sanderson 2007, Yasuda 2007, Mohamed et al. 2009, Ross et al. 2010, Bernard et al. 2012, Brodie and Giordano 2012b, Wearn et al. 2013, Gardner et al. 2014, Sastramidjaja et al. in press, Hearn et al. unpublished data). Nevertheless, even intensive felid focused camera trap surveys yield very few photographs, and photographic capture rates of the bay cat are substantially lower than that of the sympatric Sunda Clouded Leopard (Neofelis diardi), which is estimated to exist at low densities (1-4 individuals 100 km2: Brodie and Giordano 2012a, Wilting et al. 2012, Sollmann et al. 2014, Loken et al. unpublished data). Such observations have led some authors to hypothesise that the Bay Cat is found at even lower densities (Azlan and Sanderson 2007, Mohamed et al. 2009, Ross et al. 2010). It is unclear, however, whether this apparent lower detection rate is a reflection of true rarity or due to underlying factors that result in its elusiveness. Wearn et al., (2013) compared photo-capture rates of Bay Cats from a number of studies in Borneo and showed that random placement of cameras can result in higher rates than that derived from targeted placement (trails, ridgelines, and logging roads), as is typical of camera trap surveys. Wearn et al. (2013) suggested that the relative abundance of the bay cat may have hitherto been underestimated due to an underlying bias as a result of the use of non-random survey locations coupled with this felid’s particular use of space. A comparison of photo-capture rates between a randomised and a targeted survey of the Tawau Hills National Park in Sabah, however, found no evidence of elevated capture rates of this felid as a result of randomised camera deployment, and instead showed that a randomised survey approach reduced detection probability of all Bornean felids (Hearn et al.unpublished data).

It is important to highlight that while the increasing use of camera traps across the island of Borneo is slowly yielding more detections of this elusive cat, several intensive, felid-focused camera trap surveys have failed to detect this species (e.g., Tangkulap Forest Reserve, Segaliud Lokan Forest Reserve: Wilting et al. unpublished data, Sepilok Forest Reserve: Hearn, Ross and Macdonald, unpublished data, numerous surveys in Kalimantan: Cheyne and Macdonald, unpublished data), despite a habitat suitability analysis (Bornean Carnivore Symposium, Hearn et al. submitted) predicting the cat to be present. Our estimate of the Bay Cat’s current area of occupancy (AOO) must consequently be viewed with caution.

Although further research is needed to draw more firm conclusions regarding the abundance and distribution of the Borno Bay Cat, the assessors have chosen to follow a precautionary approach, and estimate that the mean density of the Bay Cat throughout its area of occupancy (AOO) is around one individual per 100 km2. Extrapolation of this density to the estimated AOO suggests the population is plausibly around 2,200 mature individuals.

The Borneo Bay Cat appears to be forest dependent, with records from hill and lowland forest as well as swamp forest (Meijaard 1997, Azlan et al. 2003, Hearn 2003, Bricknell 2003, Azlan and Sanderson 2007, Yasuda et al. 2007, Sastramidjaja et al. in press, Hearn et al. submitted). It has been recorded from selectively logged forest of various levels of disturbance (Nowell and Jackson 1996, Bricknell 2003, Hearn 2003, Kitchener et al. 2004, Meijaard et al. 2005, Ross et al. 2010, Hon 2011, Wearn et al. 2013, Mathai et al. 2014, Sastramidjaja et al. in press, Hearn et al. unpublished data), but was estimated to occur at lower local abundance in logged forests than in unlogged forest (Brodie et al. 2015). It was not recorded during an intensive, felid-focused camera trap survey of oil palm plantations in Sabah (Ross et al. 2010, Yue et al. in press). It has never been the focus of any ecological study and there is no information about its diet (Nowell and Jackson 1996, Sunquist and Sunquist 2002). It occurs in both a reddish and grey colour phase. The bay cat appears to be primarily diurnal in nature, although not strictly so (Ross et al. 2010). Nothing is known regarding the spatial ecology of this felid.

Habitat loss due to commercial logging and conversion to oil palm plantations pose the greatest threat to the Bay Cat. Oil palm plantations are likely to expand in the future as a result of the push for biofuels, and forest cover on the island of Borneo, if current deforestation rates continue, is projected to decline from 50% to less than one-third by 2020 (Rautner et al. 2005). Poaching, particularly the use of snares, poses a significant threat. Wildlife traders are aware of the species' rarity, and Bay Cats have been captured illegally from the wild for the skin and pet markets (Sunquist and Sunquist 2002, Kitchener et al. 2004, Azlan and Sanderson 2007).

Included on CITES Appendix II (as Catopuma badia). It is fully protected by national legislation across most of its range. Hunting and trade are prohibited in Indonesia (Kalimantan) and Malaysia (Sabah and Sarawak) (Nowell and Jackson 1996). It has been confirmed to occur in the following protected areas: Sabah: Danum Valley Conservation Area, (Ross et al. 2010); Sarawak - Gunung Mulu National Park (Dinets 2003), Lanjak-Entimau Wildlife Sanctuary (Azlan et al. 2003); Kalimantan: Gunung Palung National Park, Bentuang Karimun National Park (Meijaard 1997), Sungai Wain Protection Forest (Yasuda et al. 2007). The Bay Cat remains to be one of the least studied of the world’s wild cats (Sunquist and Sunquist 2002, Brodie 2009), hampering the development of conservation actions. It is therefore essential to gain an understanding of this species’ distribution, abundance, and response to anthropogenic modification of its habitat in order to better understand it’s conservation status. A detailed study of the Bay Cat’s basic ecology, including its diet and dispersal abilities is of the highest priority.

In-Place Research, Monitoring and PlanningIn-Place Land/Water Protection and Management Occur in at least one PA:YesIn-Place Species ManagementIn-Place Education Included in international legislation:Yes Subject to any international management/trade controls:Yes